Concrete curing blanket

ABSTRACT

A concrete curing blanket includes an absorbent sheet having a wicking layer, super absorbent materials, and a tissue layer, which are laminated together to form the absorbent sheet. The absorbent sheet is sized for being spread over a curing concrete slab. A vapor barrier is bonded to the tissue layer of the absorbent sheet to inhibit evaporation from the concrete curing blanket, and includes a plurality of perforations.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application for a utility patent claims the benefit of U.S.Provisional Application No. 62/110,526, filed Jan. 31, 2015.

BACKGROUND OF THE INVENTION

Field of the Invention

This invention relates generally to a concrete curing blanket, and moreparticularly to a concrete curing blanket that includes an absorbentsheet that includes a wicking layer, a super absorbent material, and atissue layer, laminated together, and having a.

Description of Related Art

Concrete strength and durability improves when the concrete isthoroughly hydrated during curing. If the concrete is kept wet for thefirst 7-10 days after setting, strength and durability thereof isincreased 75% over ordinary aging of concrete in dry surface conditions.

To keep concrete hydrated, the concrete industry has come to rely onconcrete curing blankets for covering wetted concrete and extending theduration of damp conditions on the curing surface of the concrete. Anexample of such a concrete curing blanket is disclosed in McDonald, U.S.Pat. No. 7,572,525, which teaches a curing blanket that includes a vaporbarrier, and an airlaid layer consisting of a binder material and anatural cellulose bleached fluff pulp fiber derived from wood throughKraft processing.

The prior art teaches the use of concrete curing blankets that includean airlaid layer that includes natural cellulose bleached fluff pulpfiber derived from wood through Kraft processing. However, the prior artdoes not teach a concrete curing blanket that includes an absorbentsheet that includes a wicking layer, a super absorbent material, and atissue layer, laminated together, which is covered with a vapor barrierhaving a plurality of perforations. The present invention fulfills theseneeds and provides further advantages as described in the followingsummary.

SUMMARY OF THE INVENTION

The present invention teaches certain benefits in construction and usewhich give rise to the objectives described below.

The present invention provides a concrete curing blanket that includesan absorbent sheet comprising a wicking layer and a tissue layer withsuper absorbent materials positioned therebetween. The absorbent sheetis sized for being spread over a curing concrete slab. A vapor barrieris bonded to the tissue layer of the absorbent sheet to inhibitevaporation from the concrete curing blanket.

In one embodiment, the concrete curing blanket is at least 1 meter wideand 5 meters long. In one embodiment, the vapor barrier includes aplurality of perforations.

A primary objective of the present invention is to provide a concretecuring blanket having advantages not taught by the prior art.

Another objective is to provide a concrete curing blanket that includesa combination of a wicking layer, a super absorbent material, and atissue layer, that are laminated together to form an absorbent sheet.

Another objective is to provide a concrete curing blanket that has bothsuperior wicking capabilities from the wicking layer, and also includessuperior water holding capacity due to the inclusion of the superabsorbent materials.

Another objective is to provide a concrete curing blanket that is sizedand shaped to be spread over concrete, either vertically orhorizontally, over a large area of concrete during the curing of theconcrete.

Another objective is to provide a concrete curing blanket that has avapor barrier having a plurality of perforations for maintaining waterwithin the absorbent sheet, while also allowing the absorbent sheet tobe soaked during installation, and also re-wetted periodically duringthe course of the curing process.

A further objective is to provide a concrete curing blanket that isinexpensive to manufacture, easy to use, resistant to tearing, andprovides superior hydration for extended periods of time.

Other features and advantages of the present invention will becomeapparent from the following more detailed description, taken inconjunction with the accompanying drawings, which illustrate, by way ofexample, the principles of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings illustrate the present invention. In suchdrawings:

FIG. 1 is a perspective view of a concrete curing blanket according toone embodiment of the present invention, illustrating the concretecuring blanket being positioned on a concrete slab while water is pouredonto the concrete slab and into the concrete curing blanket;

FIG. 2 is a sectional view of the concrete curing blanket taken alongline 2-2 in FIG. 1, illustrating the four layers of construction of theconcrete curing blanket in the embodiment of FIG. 1;

FIG. 3 is a side elevational view of a first step of manufacture of theconcrete curing blanket, wherein a wicking layer and a tissue layer arelaminated together to contain the super absorbent polymers therebetween,and thereby form an absorbent sheet; and

FIG. 4 is a perspective view of a second step of manufacture of theconcrete curing blanket, wherein the absorbent sheet formed in FIG. 3 isbonded to a vapor barrier to form the concrete curing blanket of FIGS. 1and 2.

DETAILED DESCRIPTION OF THE INVENTION

The above-described drawing figures illustrate the invention, a concretecuring blanket 10 that is used for providing hydration to a concreteslab C during the curing process, to provide concrete that has superiorstrength and durability.

FIG. 1 is a perspective view of one embodiment of the concrete curingblanket 10, illustrating the concrete curing blanket 10 being positionedon the concrete slab C. As illustrated in FIG. 1, the concrete curingblanket 10 is manufactured in a roll that is sized for being unrolledover the concrete slab C to effectively cover the concrete slab C. Theconcrete curing blanket 10 is at least about 1 meter wide, and about 10meters long. In a typical embodiment, the concrete curing blanket 10 is1-3 meters wide (in this case about 2.5 meters wide), and about 30-60(or more) meters long. In alternative embodiments, the measurements mayvary according to the needs of the user, but they will be sufficientlylarge to be useful in covering concrete slabs, which may be ofconsiderable size. As used in this application, the term “about” ishereby defined to include +/−10%.

As illustrated in FIG. 1, before and while the concrete curing blanket10 is being positioned on the concrete slab C, water is poured in largeamounts onto the concrete slab C and into and over the concrete curingblanket 10, so that the concrete slab C remains thoroughly hydrated, andthe concrete curing blanket 10 is thoroughly soaked. Once saturated, theconcrete curing blanket 10 maintains an optimal amount of water incontact with the surface of the concrete slab C, which optimizes thestrength and durability of the concrete when cured.

While one form of concrete slab C is illustrated herein, the term“concrete slab” is hereby defined to include any form of structure thatmay require this form of hydration, including cement walls, pillars, andother structures known in the art. Indeed, due to the superior watercarrying characteristics of the present invention, the concrete curingblanket 10 is particularly useful when used on angled or vertical cementstructures, which might otherwise be difficult to keep hydrated.

FIG. 2 is a sectional view of the concrete curing blanket 10 taken alongline 2-2 in FIG. 1. FIG. 2 illustrates the four layers of constructionof the concrete curing blanket 10 in the embodiment of FIG. 1. As shownin FIG. 2, the concrete curing blanket 10 comprises an absorbent sheet22 comprising a wicking layer 24 and a tissue layer 26 with superabsorbent materials 24 laminated therebetween. The concrete curingblanket 10 further comprises a vapor barrier 30 bonded to the tissuelayer 26 of the absorbent sheet 22.

The wicking layer 24 of FIG. 2 is a layer of material that is able toquickly wick up water from the pool of water formed on the concrete slabC (as shown in FIG. 1) as it is rolled onto the concrete slab C, so thatthe water is quickly and efficiently drawn into the concrete curingblanket 10. Water may also be poured directly onto the roll of theconcrete curing blanket 10, to assure that the concrete curing blanket10 is thoroughly hydrated. In the current embodiment, the wicking layer24 is a nonwoven fabric, in this case a spunlaced nonwoven fabriccomprising viscose. The wicking layer 24 may further comprise a polymersuch as polyethylene, polypropylene, and/or polyester, which are usefulin the bonding/lamination process, as discussed in greater detail below.In one embodiment, the wicking layer 24 comprises a combination ofviscose and polyethylene.

In one embodiment, the wicking layer 24 comprises a celluloseprecipitated from an organic solution in which no substitution of thehydroxyl groups takes place and no chemical intermediates are formed(e.g. Lyocell). In alternative embodiments, alternative or equivalentwicking materials may also be used, using formulations that would beknown to those skilled in the art, and such alternative or equivalentformulations should be considered within the scope of the presentinvention.

The super absorbent materials 24 may include super absorbent polymers,super absorbent fibers, or other similar or equivalent materials. Asused in the present application, the term “super absorbent polymers”(“SAP”) is defined to include polymers that can absorb and retainextremely large amounts of liquid relative to their own mass. Waterabsorbing SAP, classified as hydrogels, when cross linked, absorbaqueous solutions through hydrogen bonding with water molecules. A SAP'sability to absorb water is a factor of the ionic concentration of theaqueous solution. In deionized and distilled water, a SAP may absorb 500times its weight (30-60 times its own volume), although this abilitydrops to only about 10% of this amount when salt is present.

The total absorbency and swelling capacity are controlled by the type ofand degree of cross-links used to make the gel. Low densitycross-linking have a higher absorbency, which higher cross-link densityexhibits lower absorbent capacity and swell, but greater gel strengthand firmness.

SAPs are commonly made from the polymerization of acrylic acid bendedwith sodium hydroxide in the presence of an initiator to form apoly-acrylic acid sodium salt, sometimes referred to as sodiumpolyacrylate. Other materials known in the art may also be used in thismanner. In the present embodiment, the super absorbent materials 24include a sodium polycarbonate polymer, and may further includeadditional additives, as discussed in greater detail below.

As shown in FIG. 2, the concrete curing blanket 10 further includes thetissue layer 26, which in the present embodiment is a tissue fabric thatis suitable forming a bond between the absorbent sheet 22 and the vaporbarrier 30. The tissue layer 26 is a good surface for forming a good,strong, stable bond, and for preventing any bonding agents (glues,cements, bonding agents, etc.) from contaminating the super absorbentmaterials 24, and interfering with the ability of the super absorbentmaterials 24 from absorbing water. For purposes of this application, theterm “tissue layer” is defined to include tissue fabric, and also anyother materials known to those skilled in the art that is able toprovide a good bonding attachment between the absorbent sheet and thevapor barrier.

The vapor barrier 30 of FIG. 2 is a film comprising polyethylene orpolypropylene or other material that is substantially vapor impervious,to prevent dehydration of the concrete curing blanket 10. The vaporbarrier 30 may include perforations 32 so that water may be added fromthe top of the concrete curing blanket 10, so long as the perforations32 are not large enough to enable excessive drying of the concretecuring blanket 10.

FIG. 3 is a side elevational view of a first step of manufacture of theconcrete curing blanket 10, wherein the wicking layer 24 and the tissuelayer 26 are laminated together to contain the super absorbent polymerstherebetween, and thereby form the absorbent sheet 22. In thisembodiment, the super absorbent materials 24 further include a heatactivated bonding agent, which facilitates the lamination of the threesheets together in the presence of heat and pressure. In thisembodiment, the wicking layer 24, the super absorbent materials 24, andthe tissue layer 26 are all laminated together under heat and pressure,such as via one or more rollers 40. Either the rollers 40 themselves maybe heated, or a separate heater (not shown) may be included to applysuitable heat to the substrate moving through the rollers 40.

While the present embodiment uses heat, other forms of bonding agents(e.g., contact cement, hot melt adhesive, etc.) may be used duringrolling of the substrate, and may include rollers 40 that are notheated, or may omit the rollers entirely, so that the different layersare assembled in another manner known in the art.

FIG. 4 is a perspective view of a second step of manufacture of theconcrete curing blanket 10, wherein the absorbent sheet 22 formed inFIG. 3 is bonded to a vapor barrier 30 to form the concrete curingblanket 10 of FIGS. 1 and 2. In this embodiment, three of the absorbentsheets 22 are arranged side-by-side (or slightly overlapping) to bebonded to the vapor barrier 30, in this case also using rollers 40,although this is not necessarily required, as discussed above. Asdescribed above, heat, a heat activated bonding agent, contact cement,or other suitable adhesive or bonding element may be used to bond thesetwo elements together to form the final concrete curing blanket 10.

In use, the wicking layer 24 picks up water from the concrete slab C, asshown in FIG. 1, and from the wicking layer 24 the water is picked up(more slowly) by the super absorbent materials 24. While the wickinglayer 24 can pick up the water quickly, it cannot store as much water,and while the super absorbent materials 24 take longer to absorb thewater, they can in the end act as a reservoir for much larger amounts ofwater.

Following installation, if the wicking layer 24 dries, water wicks fromthe super absorbent materials 24 back into the wicking layer 24, tomaintain the proper hydration of the wicking layer 24 and the concreteslab C.

As used in this application, the words “a,” “an,” and “one” are definedto include one or more of the referenced item unless specifically statedotherwise. Also, the terms “have,” “include,” “contain,” and similarterms are defined to mean “comprising” unless specifically statedotherwise. Furthermore, the terminology used in the specificationprovided above is hereby defined to include similar and/or equivalentterms, and/or alternative embodiments that would be considered obviousto one skilled in the art given the teachings of the present patentapplication.

What is claimed is:
 1. A concrete curing blanket comprising: anabsorbent sheet comprising a wicking layer and a tissue layer with superabsorbent materials positioned between the wicking layer and the tissuelayer; wherein the wicking layer and the tissue layer are laminatedtogether with a heat activated bonding agent in the presence of heat andpressure to contain the super absorbent materials between the wickinglayer and the tissue layer, such that the wicking layer draws water upinto the super absorbent material of the absorbent sheet; wherein thewicking layer comprises lycocell, and wherein the super absorbentmaterial comprises sodium polyacrylate; a vapor barrier bonded to thetissue layer of the absorbent sheet; and wherein the concrete curingblanket is at least 1 meter wide and 5 meters long.
 2. A concrete curingblanket comprising: an absorbent sheet comprising a wicking layer and atissue layer with super absorbent materials positioned between thewicking layer and the tissue layer; wherein the wicking layer and thetissue layer are laminated together with a heat activated bonding agentin the presence of heat and pressure to contain the super absorbentmaterials between the wicking layer and the tissue layer, such that thewicking layer draws water up into the super absorbent material of theabsorbent sheet; wherein the wicking layer comprises lycocell, andwherein the super absorbent material comprises sodium polyacrylate; anda vapor barrier bonded to the tissue layer of the absorbent sheet, thevapor barrier having a plurality of perforations.
 3. A concrete curingblanket comprising: an absorbent sheet consisting of a wicking layer oflycocell and a tissue layer with superabsorbent materials positionedbetween the wicking layer of lycocell and the tissue layer, the layer oflycocell being laminated to the tissue layer with a heat activatedbonding agent in the presence of heat and pressure, such that thewicking layer of lycocell draws water up into the super absorbentmaterial of the absorbent sheet; and a vapor barrier bonded to thetissue layer of the absorbent sheet.
 4. The concrete curing blanket ofclaim 3, wherein the super absorbent materials comprise sodiumpolyacrylate.
 5. The concrete curing blanket of claim 3, wherein theconcrete curing blanket is at least 1 meter wide and 5 meters long. 6.The concrete curing blanket of claim 3, wherein the vapor barrier has aplurality of perforations.